Abstract
Peptidases are classical objects of enzymology and structural studies. However, a few protein families with experimentally characterized proteolytic activity, but unknown catalytic mechanism and three-dimensional structures, still exist. Using comparative sequence analysis, we deduce spatial structure for one of such families, namely, U40, which contains just one P5 protein from bacteriophage phi-6. We show that this singleton sequence possesses conserved sequence motifs characteristic of lysozymes and is a distant homolog of lytic transglycosylases that cleave bacterial peptidoglycan. The structure of the P5 protein is therefore predicted to adopt the lysozyme-like fold shared by T4, λ, C-type, G-type lysozymes, and lytic transglycosylases. Since previous biochemical experiments with P5 of phi-6 have indicated that the purified enzyme possesses endopeptidase activity and not glycosidase activity, our results point to the possibility of a newly evolved molecular function and call for further experimental characterization of this unusual P5 protein.
Original language | English (US) |
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Pages (from-to) | 1370-1374 |
Number of pages | 5 |
Journal | Protein Science |
Volume | 14 |
Issue number | 5 |
DOIs | |
State | Published - May 2005 |
Keywords
- Bacteriophage phi-6
- Comparative phage genomics
- Lysozyme
- Lytic transglycosylase
- Peptidase
- Structure prediction
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology